Question

Select all of the answers that apply. Which of the following events define the Proterozoic eon? 1.eukaryotic cells first seen 2.stable continents 3.first bacterial fossils 4.Cambrian explosion 5.oxygen builds up in atmosphere

Answer 1

proterozoic eon - oxygen builds up in atmosphere. 

Answer 2

Option 1.Eukaryotic cells first seen

Option 5. oxygen builds up in the atmosphere

Step-by-step explanation :

• The name Proterozoic eon is derived from a Greek word which means earlier life.

• This eon represents the time just before complex life started proliferating on earth.

• One of the most important events that took place during this eon was build up of oxygen in the atmosphere.

The fossil evidence also shows the occurrence of advanced single-celled eukaryotes.

So the events that define the Proterozoic eon are eukaryotic cells first seen and oxygen build up in the atmosphere.